# Accruing Key Rewards

* To accrue key rewards, a Sentry Key must participate in a Challenge. 
* A Challenge is created approximately once every hour. This means there will be \~720 Challenges per month. 
* Each Sentry Key that participates in a Challenge will receive a pro rata share of the Network Reward, as described in [Network Rewards](https://xai-foundation.gitbook.io/xai-network/en/about-xai/xai-tokenomics/network-rewards). 
* By default, each Sentry Key has a 0.01% probability of participating in a Challenge.  This is known as the Bronze Tier.
* The probability that a Sentry Key will participate in a Challenge will increase if the Key is staked in a Pool with higher Tier than Bronze.  Each Reward Tier is explained in the section, [Staking Rewards and Tiers](https://xai-foundation.gitbook.io/xai-network/en/staking-explained/staking-rewards-and-tiers).
* To maximize the potential of earning Network Rewards from a Sentry Key, it is strongly recommended that you participate in a Pool and run the Sentry Wallet (a.k.a. Operator) 24 hours a day, 7 days a week.